You're not having much luck with it unfortunately!
That water is muck!
I'm very lucky to have crystal clear water at my parents house but the same muck in the apt. The difference is crazy. Those watermarks dry in in minutes and just won't budge!
If I were you, I'd personally opt for sourcing a cheap supplier of purified water and buying in bulk then connecting up the power washer to the drum.
Yes you can sort out the filters but it's hit and miss and several variables effect their results. One simple problem I had was a reduction in temperature by just a few degrees caused an awful scale build up. Try again if you can keep costs low but from then I'd get to know a person down the road with better water or a cheap supplier of purified water.
P.S. I'd like to see you prove me wrong and get the system working. I just wouldn't be in a place long enough to warrant installing such a system. Good luck!